net.sf.saxon.expr
Interface XPathContext

All Known Implementing Classes:

EarlyEvaluationContext, XPathContextMinor

public interface XPathContext

This class represents a context in which an XPath expression is evaluated.

Method Summary

void	changeOutputDestination(java.util.Properties props, javax.xml.transform.Result result, boolean isFinal, int hostLanguage, int validation, SchemaType schemaType) Set a new output destination, supplying the output format details.
ValueRepresentation	evaluateLocalVariable(int slotnumber) Get the value of a local variable, identified by its slot number
XPathContext	getCaller() Get the calling XPathContext (the next one down the stack).
java.util.Comparator	getCollation(java.lang.String name) Get a named collation
Configuration	getConfiguration() Get the Configuration
Item	getContextItem() Get the context item
int	getContextPosition() Get the context position (the position of the context item)
Controller	getController() Get the Controller.
GroupIterator	getCurrentGroupIterator() Get the current group iterator.
SequenceIterator	getCurrentIterator() Get the current iterator.
Mode	getCurrentMode() Get the current mode.
net.sf.saxon.regex.RegexIterator	getCurrentRegexIterator() Get the current regex iterator.
Template	getCurrentTemplate() Get the current template.
java.util.Comparator	getDefaultCollation() Get the default collation
int	getLast() Get the context size (the position of the last item in the current node list)
ParameterSet	getLocalParameters() Get the local (non-tunnel) parameters that were passed to the current function or template
NamePool	getNamePool() Get the Name Pool
InstructionInfoProvider	getOrigin() Get information about the creating expression or other construct.
int	getOriginatingConstructType() Get the type of location from which this context was created.
SequenceReceiver	getReceiver() Get the Receiver to which output is currently being written.
StackFrame	getStackFrame() Get a reference to the local stack frame for variables.
ParameterSet	getTunnelParameters() Get the tunnel parameters that were passed to the current function or template.
XPathContextMajor.XSLTContext	getXSLTContext() Get the XSLT-specific part of the context
boolean	isAtLast() Determine whether the context position is the same as the context size that is, whether position()=last()
XPathContextMajor	newCleanContext() Construct a new context without copying (used for the context in a function call)
XPathContextMajor	newContext() Construct a new context as a copy of another.
XPathContextMinor	newMinorContext() Construct a new minor context.
void	setCaller(XPathContext caller) Set the calling XPathContext
void	setCurrentIterator(SequenceIterator iter) Set a new sequence iterator.
void	setLocalVariable(int slotnumber, ValueRepresentation value) Set the value of a local variable, identified by its slot number
void	setOrigin(InstructionInfoProvider expr) Set the creating expression (for use in diagnostics).
void	setOriginatingConstructType(int loc) Set the type of creating expression (for use in diagnostics).
void	setReceiver(SequenceReceiver receiver) Change the Receiver to which output is written
void	setTemporaryReceiver(SequenceReceiver out) Set the receiver to which output is to be written, marking it as a temporary (non-final) output destination.
boolean	useLocalParameter(int fingerprint, LocalParam binding, boolean isTunnel) Use local parameter.

Method Detail

newContext

public XPathContextMajor newContext()

Construct a new context as a copy of another. The new context is effectively added to the top of a stack, and contains a pointer to the previous context

newCleanContext

public XPathContextMajor newCleanContext()

Construct a new context without copying (used for the context in a function call)

newMinorContext

public XPathContextMinor newMinorContext()

Construct a new minor context. A minor context can only hold new values of the focus (currentIterator) and current output destination.

getXSLTContext

public XPathContextMajor.XSLTContext getXSLTContext()

Get the XSLT-specific part of the context

getLocalParameters

public ParameterSet getLocalParameters()

Get the local (non-tunnel) parameters that were passed to the current function or template

Returns:

a ParameterSet containing the local parameters

getTunnelParameters

public ParameterSet getTunnelParameters()

Get the tunnel parameters that were passed to the current function or template. This includes all active tunnel parameters whether the current template uses them or not.

Returns:

a ParameterSet containing the tunnel parameters

setOrigin

public void setOrigin(InstructionInfoProvider expr)

Set the creating expression (for use in diagnostics). The origin is generally set to "this" by the object that creates the new context. It's up to the debugger to determine whether this information is useful. Where possible, the object will be an InstructionInfoProvider, allowing information about the calling instruction to be obtained.

setOriginatingConstructType

public void setOriginatingConstructType(int loc)

Set the type of creating expression (for use in diagnostics). When a new context is created, either this method or setOrigin(net.sf.saxon.trace.InstructionInfoProvider) should be called.

Parameters:

loc - The originating location: the argument must be one of the integer constants in class Location

getOrigin

public InstructionInfoProvider getOrigin()

Get information about the creating expression or other construct.

getOriginatingConstructType

public int getOriginatingConstructType()

Get the type of location from which this context was created.

getController

public Controller getController()

Get the Controller. May return null when running outside XSLT or XQuery

getConfiguration

public Configuration getConfiguration()

Get the Configuration

getNamePool

public NamePool getNamePool()

Get the Name Pool

setCaller

public void setCaller(XPathContext caller)

Set the calling XPathContext

getCaller

public XPathContext getCaller()

Get the calling XPathContext (the next one down the stack). This will be null if unknown, or if the bottom of the stack has been reached.

setCurrentIterator

public void setCurrentIterator(SequenceIterator iter)

Set a new sequence iterator.

getCurrentIterator

public SequenceIterator getCurrentIterator()

Get the current iterator. This encapsulates the context item, context position, and context size.

Returns:

the current iterator, or null if there is no current iterator (which means the context item, position, and size are undefined).

getContextPosition

public int getContextPosition()
                       throws DynamicError

Get the context position (the position of the context item)

Returns:

the context position (starting at one)

Throws:

DynamicError - if the context position is undefined

getContextItem

public Item getContextItem()

Get the context item

Returns:

the context item, or null if the context item is undefined

getLast

public int getLast()
            throws XPathException

Get the context size (the position of the last item in the current node list)

Returns:

the context size

Throws:

XPathException - if the context position is undefined

isAtLast

public boolean isAtLast()
                 throws XPathException

Determine whether the context position is the same as the context size that is, whether position()=last()

Throws:

XPathException

getCollation

public java.util.Comparator getCollation(java.lang.String name)
                                  throws XPathException

Get a named collation

Throws:

XPathException

getDefaultCollation

public java.util.Comparator getDefaultCollation()

Get the default collation

useLocalParameter

public boolean useLocalParameter(int fingerprint,
                                 LocalParam binding,
                                 boolean isTunnel)
                          throws XPathException

Use local parameter. This is called when a local xsl:param element is processed. If a parameter of the relevant name was supplied, it is bound to the xsl:param element. Otherwise the method returns false, so the xsl:param default will be evaluated

Parameters:

fingerprint - The fingerprint of the parameter name

binding - The XSLParam element to bind its value to

isTunnel - True if a tunnel parameter is required, else false

Returns:

true if a parameter of this name was supplied, false if not

Throws:

XPathException

getStackFrame

public StackFrame getStackFrame()

Get a reference to the local stack frame for variables. Note that it's the caller's job to make a local copy of this. This is used for creating a Closure containing a retained copy of the variables for delayed evaluation.

Returns:

array of variables.

evaluateLocalVariable

public ValueRepresentation evaluateLocalVariable(int slotnumber)

Get the value of a local variable, identified by its slot number

setLocalVariable

public void setLocalVariable(int slotnumber,
                             ValueRepresentation value)

Set the value of a local variable, identified by its slot number

changeOutputDestination

public void changeOutputDestination(java.util.Properties props,
                                    javax.xml.transform.Result result,
                                    boolean isFinal,
                                    int hostLanguage,
                                    int validation,
                                    SchemaType schemaType)
                             throws XPathException

Set a new output destination, supplying the output format details.
Note that it is the caller's responsibility to close the Writer after use.

Parameters:

props - properties defining the output format

result - Details of the new output destination

isFinal - true if the destination is a final result tree (either the principal output or a secondary result tree); false if

hostLanguage -

Throws:

XPathException - if any dynamic error occurs; and specifically, if an attempt is made to switch to a final output destination while writing a temporary tree or sequence

setTemporaryReceiver

public void setTemporaryReceiver(SequenceReceiver out)

Set the receiver to which output is to be written, marking it as a temporary (non-final) output destination.

Parameters:

out - The SequenceOutputter to be used

setReceiver

public void setReceiver(SequenceReceiver receiver)

Change the Receiver to which output is written

getReceiver

public SequenceReceiver getReceiver()

Get the Receiver to which output is currently being written.

Returns:

the current Receiver

getCurrentMode

public Mode getCurrentMode()

Get the current mode.

Returns:

the current mode

getCurrentTemplate

public Template getCurrentTemplate()

Get the current template. This is used to support xsl:apply-imports

Returns:

the current template

getCurrentGroupIterator

public GroupIterator getCurrentGroupIterator()

Get the current group iterator. This supports the current-group() and current-grouping-key() functions in XSLT 2.0

Returns:

the current grouped collection

getCurrentRegexIterator

public net.sf.saxon.regex.RegexIterator getCurrentRegexIterator()

Get the current regex iterator. This supports the functionality of the regex-group() function in XSLT 2.0.

Returns:

the current regular expressions iterator